In this Oct. 22, file photo, President Barack Obama, left, and Republican presidential nominee Mitt Romney laugh at the conclusion of the the third presidential debate at Lynn University in Boca Raton, Fla. Michael Reynolds / AP Photo

MADISON, Wis. (AP) — President Barack Obama and Mitt Romney storm into the final day of their long presidential contest, mounting one last effort to protect their flanks while engaging in the toughest battleground of all — Ohio.

The two campaigns were ready to leave matters in the hands of voters and their schedules left little doubt where the election would be won or lost. Obama was holding rallies in Wisconsin and Iowa on Monday. Romney was cutting a broader swath, with events in Florida, Virginia and New Hampshire.

But the richest prize is Ohio, and both Obama and Romney were rallying their supporters in its capital, Columbus.

Whoever wins Ohio has a simpler path to amass the 270 electoral votes needed to claim the presidency. With national polls showing the two candidates locked in a virtual tie, the outcome in a handful of key states will determine who occupies the White House for the next four years.

For Obama, Iowa, Wisconsin and Ohio are his firewall. "I think it's going to hold firm," Vice President Joe Biden told a rally in Ohio Sunday. Victories in those three states, barring a huge upset in a state like Pennsylvania, would virtually assure him re-election. "I think we're going to win clearly," Biden said.

Romney voiced more guarded optimism. In Cleveland, discussing the chances of Obama's re-election, Romney said, "It's possible, but not likely."

A final national NBC/Wall Street Journal Poll showed Obama getting the support of 48 percent of likely voters, with Romney receiving 47 percent. A Washington Post-ABC News tracking poll had Obama at 49 and Romney at 48. A Pew Research Center poll released Sunday showed Obama with a three-point edge over Romney, 48 percent to 45 percent among likely voters.

Defying the odds, Romney drew one of his largest crowds Sunday in Pennsylvania, a state where Obama was holding onto a lead but where Romney aides said they detected soft support for the president. Despite a delayed arrival, Romney rallied thousands on a farm in a Philadelphia suburb on a cold night, taking the podium as loudspeakers blared the theme from "Rocky." The sign of energy in a key swing area of the state was only tempered by some early exits by supporters seeking to escape the cold.

Meanwhile, about 30 million people have already voted in 34 states and the District of Columbia, either by mail or in person, although none will be counted until Election Day on Tuesday. More than 4 million of the ballots were cast in Florida, where Democrats filed a lawsuit demanding an extension of available time. A judge granted their request in one county where an early voting site was shut down for several hours Saturday because of a bomb scare.

Both men were spending the final days of the campaign presenting themselves as can-do leaders willing to break partisan logjams in Washington.

The former Massachusetts governor warned that a second Obama term would threaten the American economy because of the president's inability to work with Congress. "He's ignored them, he's attacked them, he's blamed them," Romney said.

Obama cited bipartisan work on middle-class tax cuts and on ending the Pentagon's don't-ask-don't-tell policy, but warned that he would not compromise away his priorities, such as health care. "I'm not willing to pay that price," he said.

At stops, Obama has been telling crowds, "If you want to break the gridlock in Congress, you'll vote for leaders who feel the same way, whether they are Democrats or Republicans or independents." But the local candidates he often cites are inevitably Democrats.

As the race approached its conclusion, the two candidates engaged in their own personal moments with friends and close aides, an acknowledgement that no matter who won, this was the end of the campaign.

Longtime Obama chums Mike Ramos, a childhood friend from Hawaii, and Marty Nesbitt, a friend from Chicago, joined the president on Air Force One. On Monday, longtime adviser and former White House press secretary Robert Gibbs and former personal aide Reggie Love were to join the entourage.

Aboard Air Force One, the president also was making calls to Democratic candidates to wish them well, including Senate contender Elizabeth Warren in Massachusetts.

Obama will also benefit from some star power Monday. Rock legend Bruce Springsteen is joining him at all three campaign rallies, and rapper Jay-Z will join them in Columbus.

Romney, for his part, has appeared more relaxed on the campaign trail, where he's been joined by most of his longtime senior aides. Much of the planning and strategy is finished, they say, and they wanted to spend the final days of the campaign at Romney's side.

Adviser Kevin Madden said Romney was spending much of his time working on his laptop, reading and writing in his journal. The Republican candidate also recently joined his aides in an hour-and-a-half discussion about their favorite movies. Romney's? "O Brother, Where Art Thou," which stars Obama pal George Clooney.

As aides for both candidates looked for early marks of success, there were signs for the superstitious. Since 1936, with only one exception, whenever the Washington Redskins won on the Sunday before the election, the incumbent party would retain the White House. On Sunday, the Redskins lost to the Carolina Panthers, giving hope to Republicans.

But the Obama camp often compares this election to 2004, when President George W. Bush held the White House in his race against Democrat John Kerry. That year was the exception to the rule; the Redskins lost, and so did Kerry.

More on the 24th Congressional District race in Central New York

All three candidates participated in live Q&As with syracuse.com readers twice this fall. You can read the transcripts of their sessions below: